1. Field of the Invention
The present invention relates to a light source, and particularly to a light emitting device.
2. Description of the Related Art
A White Organic Light Emitting Diode (WOLED) can be used as a light source applied in a lighting field or a display field.
A WOLED is generally divided into two types: a WOLED with a single light-emitting layer and a WOLED with a multiple light-emitting layers. A WOLED with a single light-emitting layer generally achieves mixed white light by doping differently colored light emitting materials with predetermined concentrations into the light-emitting layer. It is difficult to control the doping concentrations of the light-emitting materials in the WOLED with a single light-emitting layer; interference exists between the differently colored light-emitting materials, whereby it is difficult to obtain pure white light. A WOLED with multiple light-emitting layers generally generates white light through three stacked red, green, and blue light-emitting materials. A mixture of the three colored light obtains the white light. Manufacture of the WOLED with multiple light-emitting layers is complicated. Moreover, the differently colored light emitting materials in different layers will absorb energy from each other, resulting in a reduced lighting efficiency.
In summary, the manufacture of a traditional WOLED is complicated, the lighting efficiency thereof is not high, and the quality of the white light obtained thereby is not good enough.
Thus, it is necessary to provide a new technical solution which can solve the technical problems mentioned above.